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The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

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<h4><a name = "tag_000_010_851">&nbsp;</a>NAME</h4><blockquote>
y0, y1, yn - Bessel functions of the second kind
</blockquote><h4><a name = "tag_000_010_852">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

#include &lt;<a href="math.h.html">math.h</a>&gt;

double y0(double <i>x</i>);
double y1 (double <i>x</i>);
double yn (int <i>n</i>, double <i>x</i>);
</code>
</pre>
</blockquote><h4><a name = "tag_000_010_853">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>y0()</i>,
<i>y1()</i>
and
<i>yn()</i>
functions compute Bessel functions of
<i>x</i>
of the second kind of orders 0, 1 and
<i>n</i>
respectively.
The value of
<i>x</i>
must be positive.
<p>
An application wishing to check for error situations should set
<i>errno</i>
to 0 before calling
<i>y0()</i>,
<i>y1()</i>
or
<i>yn()</i>.
If
<i>errno</i>
is non-zero on return, or the return value is NaN, an error has occurred.
</blockquote><h4><a name = "tag_000_010_854">&nbsp;</a>RETURN VALUE</h4><blockquote>
Upon successful completion,
<i>y0()</i>,
<i>y1()</i>
and
<i>yn()</i>
will return the relevant Bessel value of <i>x</i> of the second kind.
<p>
If
<i>x</i>
is NaN,
NaN is returned and
<i>errno</i>
may be set to [EDOM].
<p>
If the
<i>x</i>
argument to
<i>y0()</i>,
<i>y1()</i>
or
<i>yn()</i>
is negative, -HUGE_VAL or NaN is returned, and
<i>errno</i>
may be set to [EDOM].
<p>
If
<i>x</i>
is 0.0, -HUGE_VAL is returned and
<i>errno</i>
may be set to [ERANGE] or [EDOM].
<p>
If the correct result would cause underflow, 0.0 is returned and
<i>errno</i>
may be set to [ERANGE].
<p>
If the correct result would cause overflow, -HUGE_VAL or 0.0 is returned and
<i>errno</i>
may be set to [ERANGE].
</blockquote><h4><a name = "tag_000_010_855">&nbsp;</a>ERRORS</h4><blockquote>
The
<i>y0()</i>,
<i>y1()</i>
and
<i>yn()</i>
functions may fail if:
<dl compact>

<dt>[EDOM]<dd>
The value of
<i>x</i>
is negative or NaN.

<dt>[ERANGE]<dd>
The value of
<i>x</i>
is too large in magnitude, or
<i>x</i>
is 0.0, or the correct result would cause overflow or underflow.

</dl>
<p>
No other errors will occur.
</blockquote><h4><a name = "tag_000_010_856">&nbsp;</a>EXAMPLES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_010_857">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_010_858">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_010_859">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="isnan.html">isnan()</a></i>,
<i><a href="j0.html">j0()</a></i>,
<i><a href="math.h.html">&lt;math.h&gt;</a></i>.
</blockquote><h4>DERIVATION</h4><blockquote>
Derived from Issue 1 of the SVID.
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UNIX &reg; is a registered Trademark of The Open Group.<br>
Copyright &copy; 1997 The Open Group
<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]

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